This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This project investigates sex differences in the social, emotional, cognitive and neuroendocrine consequences of neonatal and post-pubertal amygdalectomy in rhesus monkeys living in complex semi-natural social groups. Unlike the severely socially restricted conditions of previous studies, our large monkey groups have multiple matrilines and all age and sex classes allowing investigating amygdala function under social conditions it is likely designed to deal with. This project tracks the development of these systems and relates changes in juvenile function to the pubertal transition and adult social behavior. We have now successfully created forty-one monkey subjects in two annual cohorts, including 9 male and 8 female neonatally amygdalectomized subjects, with the other 24 subjects serving as juvenile controls. Neonatal gonadal function, anxiety, fear, and maternal attachment are in the process of being assessed along with extensive observations of social interactions in the subjects'natal group during the first four years of life. At 2yr, continuously available computer kiosks will be used to assess object and spatial memory span and object discrimination. Starting at 1.25yr females have been intensely sampled to assess pubertal timing as well as pubertal changes in social and sexual behavior. Surprisingly, the neonatally amygdalectomized female) went through menarche at 1.5years, a full year earlier than any control female in our colony has gone through puberty. We have continued weekly focal observations of behavior, neonatal imitation, and LabTab performance has been collected on these subjects. Sample sizes are now sufficient for data analysis, which is currently under way.